In the transport of articles by highway on a flat bed trailer, there is the continual problem of being able to satisfactorily securing the load upon the trailer so that it will not become dislodged. The normal method is to use hold down chains which are secured to the bed of the trailer, pass over the load, and are tightened with a toggle arrangement or a simple winch mechanism. However, when transporting certain kinds of load such as pipe, the resistance to longitudinal movement of the pipe upon the trailer is quite low. There is therefore a great tendency for the pipe to move through the chains when the trailer is decelerated and it is known for such pipes to pierce the cab often with fatal consequences for the driver. This is a very real problem in the transport of pipes by highway as it must be taken into consideration that these trucks frequently operate on poorly developed roads having very steep grades, sharp turns and soft shoulders and there is no protection for the driver in the cab of the tractor to prevent pipes from piercing the cab. The situation is particularly dangerous during the winter months when the pipes are covered with frost and there is no possible way to positively hold them in position with tie down chains no matter how much tension is placed upon the chains.
In an attempt to overcome this problem and divert a moving load away from a tractor cab, it has been suggested that a snowplow shaped deflector be fastened onto the back of the cab. Such a deflector is disclosed in Canadian Patent No. 687,611. The device in this patent will however not function satisfactorily and is not used in the industry. This patented deflector it will be noted is secured to a cab, however the light metal of a cab will never carry the weight of a shield of adequate strength to give protection against a piece of pipe weighing perhaps several tons shooting forward ten or twelve feet from a trailer load. Also, the fact that the shield is divided in the middle would provide no protection whatsoever if a large diameter pipe hit the shield at its mid point. This type of accident would just crush the shield and the cab together. In addition to the fact that the shield could not be strong enough to provide reasonable protection when it is mounted on the cab as shown in this patent, it eliminates the drivers full "rear window view" of his load and of his winch, so making the mere hooking up of the trailer to the tractor unit a more difficult operation and also preventing direct viewing of the load when winching. Furthermore, the device in the patent takes up the space which is normally used in a pipe carrying tractor trailer unit to accommodate the winch, chains and further paraphernalia which are used with the loading and unloading of this type of load. There is also the possibility with this prior art patented device that, due to the distance between the load and the deflector, during deceleration on a steep hill, a pipe could slide forwardly and jam into the deflector so holding the cab and trailer in a rigid position and preventing steering of the tractor. A dangerous situation could therefore quite easily be encountered. Finally, if the deflector of the patent did deflect a load which was sliding forwardly, part would be deflected off the road and part would be deflected into the path of oncoming traffic. This would also create a dangerous situation.